The invention relates to an HF plug connection system with a standardized socket insert and corresponding plug as the plug connector parts, in which system an earthed screening runs from cable to cable through both parts of the plug connector.
Various makes of plug connection system are available on the market, for example with four, six, eight, ten, twelve, fourteen or more poles, as the contacts are known. In these systems, incorrect connections are avoided as the plug connectors have certain geometric shapes and/or external dimensions or are fitted with a coding device.
Plug connection systems are used in particular for electrical connections in main communication and peripheral equipment for example ISDN, telephones, terminals, modems, PCs, host or data network systems.
Conventional HF cables of the known types usually consist of copper wires embedded in a flexible mass, a peripheral shield and an outer insulating sheath. The shield comprises at least a braided, woven or knitted fabric of copper wires, which may on the inside rest on an aluminium foil. Such an HF cable has a defined minimum permitted bending radius which with the usual makes is at least four to five times the external diameter of the cable. If the bending radius is less than this minimum, faults or even failures in operation can be expected.
In the area of HF plug connection systems, the cable screening of a socket insert and associated plug must be electrically connected together or else the earth connection cannot be guaranteed.
In conventional makes, this is generally achieved in one of the following basic methods:
The screening of the two HF cables is connected via a wire of for example 0.5 mm diameter running through the entire plug connection system. At high frequencies (HF) up to approx 1 MHz, the electrical resistance for an earth current is relatively low and negligible because of the low Ohmic value. At higher frequencies, in particular with the frequencies of approx 10.sup.8 Hz (=100 MHz), normal in modern high tech sectors, the electrical resistance rises to the region of 3-4 kOhm on use of conventional wires, which makes effective earthing impossible. PA1 In another known variant, the screening of the two cables is connected not via a wire but with a conductor of greater cross-section running through the plug system. This design form however has the disadvantage that the cables can only be connected rigidly in one direction or the other. For changes of direction, the HF cable must be bent which can lead to the problems mentioned above. The HF plug connection system with a large bending radius for the HF cable requires a corresponding installation length and hence in addition to the greater space requirements, higher installation costs. PA1 The transfer resistance can be kept in the range of a few Ohm even at frequencies in the range of approx 10.sup.8 Hz. PA1 Thanks to the complete large area flexible screening at least in the area outside the cable sheath, i.e. in the area of the exposed wires, the cable can be adapted by bending to any angle without the risk of kinking or having too tight a bending radius. PA1 A side cable connection in relation to the plug direction at any angle can shorten the installation length of the HF plug system. PA1 With the housing cover closed, the flexible plate in the screening can be bent at a second bending zone as the angle of the cable end changes. After removing the housing cover and bending the shield connection back at an exposed first bending zone, the installation area for the cable is fully exposed. PA1 The simple design allows the advantages with no loss of economy.
The object of the present invention is therefore to create an HF plug connection system of the type described initially which has a low electrical resistance of a few Ohm even at frequencies in the range of approx 10.sup.8 Hz, which does not stress the HF cable with bending radii which are too low and which has a shorter installation length.